The classical method for making soft- or liquid-centered food products, notably candies such as chocolate-covered cherries, employs invertase as an ingredient in a sugar fondant center (U.S. Pat. No. 1,437,816 to Paine and Hamilton). During manufacture, the sugar fondant center is firm and easily enrobed with chocolate or another coating; on storage, the enzyme slowly hydrolyzes sucrose to invert sugar. The invert sugar is more soluble than sucrose in the moisture of the fondant, so it melts under the coating, converting the firm center into a creamy liquid. The process requires sucrose as the enzyme substrate, however, and so is unsuitable for centers containing other sweeteners.
Other methods require specialized, mechanically intricate equipment and/or multistep manufacturing processes involving shell formation and filling. For example, in U.S. Pat. No. 3,666,388 to Oberwelland and Klahn, hollow sweetmeats are made by spinning an open top mold containing a measured quantity of castable confectionery material and cooling the body until it forms a shell, which is subsequently filled. U.S. Pat. No. 4,260,596 to Mackles discloses an analogous method for preparing a hard outer shell covering by chilling a molten mannitol composition in a hemisphere mold until a sufficiently thick wall has been formed; the shells are then filled.
U.S. Pat. No. 3,496,886 to Fohr discloses a process involving the cooling of a liquid filling to a temperature below the sugar saturation temperature before casting the rapidly cooled filling liquid into molds to form a candy unit with a hard crust. U.S. Pat. No. 4,517,205 to Aldrich discloses codeposition of a two-component hard candy wherein the components have specified sugar contents and specific gravities. U.S. Pat. No. 4,229,484 to Steels and Dacey discloses a method of making center-filled bars of chocolate by depositing shell forming and filling materials into molds from a depositor comprising, for example, two separated and independently heated hoppers by means of pairs of independently operated plungers. Other apparatuses have been designed to fashion fold-over soft center-filled confections (U.S. Pat. No. 5,035,905 to Knebl) and soft-centered ropes (U.S. Pat. No. 4,938,128 to Knebl).
It would be desirable to provide a process for making filled and layered multi-textured food products that does not involve food additives or specialized equipment. It would also be desirable to provide a process for making soft- and liquid-centered confections that do not have sucrose as the exclusive sweetener in the center.